1. Field of the Invention
This invention relates to a technique for a portable communication terminal capable of utilizing a plurality of wireless paths with different billing systems to select a communication path.
2. Description of Related Art
It has been made possible for a portable communication terminal such as a portable telephone set to access a communication network and acquire a data file of music, pictures or the like from a given server device. Patent Document 1 (JP-3164085B) and Patent Document 2 (JP 2002-64869A) disclose techniques for reducing the communication cost of such a service. When the volume of communication data to be transmitted between a client and a server exceeds a predetermined level in the system disclosed in Patent Document 1, the data to be transmitted is divided and sent out by way of a communication network with a measured rate billing system and a communication network with a connection time billing system. A portable wireless terminal of Patent Document 2 uses a non-public wireless line for downloading contents and a public mobile communication system for settlement of accounts.
However, with the system of Patent Document 1, if the contents are partly transmitted by way of a communication network with a connection time billing system, it will be difficult to reduce the communication cost because the transmission time becomes longer as the communication data increases. The system of Patent Document 2, on the other hand, is accompanied by a problem that the mobility of the user who is trying to download contents is limited because all the contents have to be acquired from a given server by way of a non-public wireless line and hence the user has to remain in the area where the line can be captured.